clutch slave cylinder bleeding problem
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Joined: Nov 2020
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clutch slave cylinder bleeding problem
I'm trying to bleed my slave cylinder on my 1990 and I think I'm doing it right. 2 man method, bleeder valve closed while the guy up top pumps the clutch 10 times then holds it to the floor while I crack open the bleeder valve and then close it.
I've done brakes before and this exact method has worked, but when I do it for this slave cylinder I hear no hiss of air or major spurt of fluid. the most I've gotten is a little trickle when I first cracked the valve.
any ideas?
thanks
I've done brakes before and this exact method has worked, but when I do it for this slave cylinder I hear no hiss of air or major spurt of fluid. the most I've gotten is a little trickle when I first cracked the valve.
any ideas?
thanks
Drifting
Joined: Apr 2020
Posts: 1,925
Likes: 610
From: Orange, CA
For one, it's possible that the seal inside the clutch slave is installed backwards. This was a problem back in the day, and apparently can still be a problem with the Chinese remans. Here's info: http://www.zfdoc.com/CHS_Actuator_Seal_Fault.htm
For another, our clutch hydraulics suck so bleeding them 'traditionally' can be a major PITA. You at least have a 90 so it's not as bad as the 91-96 system, but it'd still be good to reverse bleed it instead of trying to gravity bleed or pedal bleed.
Best of luck.
For another, our clutch hydraulics suck so bleeding them 'traditionally' can be a major PITA. You at least have a 90 so it's not as bad as the 91-96 system, but it'd still be good to reverse bleed it instead of trying to gravity bleed or pedal bleed.
Best of luck.
Last edited by Nomake Wan; Jun 13, 2021 at 11:05 PM.
Safety Car
Joined: Aug 2013
Posts: 4,429
Likes: 605
From: Minneapolis Mn
If this is the external slave like on the 86, I have a suggestion. First bleed it as best you can. Now fill up the reservoir with brake fluid and the cap off. Pump the clutch pedal 8-10 times rapidly and the last time hold the pedal to the floor for about 5 minutes. At the end of the 5 minutes, slide your foot and let it pop up on it's own (you may have to do it a couple of times). My theory - air in the system will go up the line to the gooseneck above the master cylinder while you hold the clutch down then is pushed out when you release the pedal.
I got this info from a former GM mechanic and it solved my air in the clutch issue. Hope it helps and it doesn't cost a thing except some time.
I got this info from a former GM mechanic and it solved my air in the clutch issue. Hope it helps and it doesn't cost a thing except some time.
Safety Car
Joined: May 2001
Posts: 4,759
Likes: 1,647
From: Fairfax Virginia
Reverse Bleeding is the best way to bleed those GM Clutch master cylinders just like Nomake wan suggests.
I have the Phoenix Reverse Bleeding system and it saved our butt multiple times on our hydraulic clutch in our Pick Up over 200,000 miles and several clutches.
The mechanic that did the clutch would always have trouble until I brought over the Phoenix Bleeder and Pushed the air up and out from the top. It really makes the job easy. I use it on everything that needs to be bled, Motorcycles, Cessna 172 and Boats. They are not expensive and are re-build-able when and IF needed. This device makes flushing brake fluid very easy for even one man.
I have the Phoenix Reverse Bleeding system and it saved our butt multiple times on our hydraulic clutch in our Pick Up over 200,000 miles and several clutches.
The mechanic that did the clutch would always have trouble until I brought over the Phoenix Bleeder and Pushed the air up and out from the top. It really makes the job easy. I use it on everything that needs to be bled, Motorcycles, Cessna 172 and Boats. They are not expensive and are re-build-able when and IF needed. This device makes flushing brake fluid very easy for even one man.
